Air bag module diffuser

ABSTRACT

An air bag module comprises an air bag having an interior cavity. The air bag has an air bag opening in communication with the interior cavity. The air bag module has an air bag inflator with an outlet for inflating the air bag. At least one vane extends from the air bag opening into the interior cavity of the air bag.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a passenger side air bag module.

[0002] An air bag module typically comprises an air bag and an air baginflator. When a severe crash is detected by a vehicle's crash detectionsystem, the system may instruct the air bag module to deploy. If thisevent occurs, the air bag inflator rapidly discharges an inflation gasat a very high temperature into the air bag. The high temperature of thegas causes its rapid expansion, thereby inflating the air bag to form acushion against vehicle impact for a vehicle occupant. Preferably, theair bag should deploy towards the vehicle occupant to maximizecushioning. However, challenges arise in the design of an air bag modulefor a passenger side air bag. Specifically, due to the shape ofpassenger side air bag inflators, inflation gas from the air baginflator may discharge toward the side of the vehicle occupant. As aconsequence, the air bag may deploy toward the side of the vehicleoccupant rather than in the direction of the occupant.

[0003] Manufacturers have sought to overcome this design challenge byusing a vent to redistribute the flow of inflation gas across the mouthof the air bag through guide structures, such as holes or vanes, locatedbetween the air bag inflator and the air bag. Vent holes are not veryeffective in redistributing air flow. Moreover, the vanes thatmanufacturers currently use extend between the air bag inflator and theair bag and are located outside of the air bag. Applicant has discoveredthat these vanes draw heat away from the inflation gas and consequentlyreduce its ability to expand the air bag.

[0004] A need therefore exists for an air bag module that redirects theflow of inflation gas towards the vehicle occupant without significantheat loss.

SUMMARY OF THE INVENTION

[0005] The present invention comprises an air bag module, having an airbag and air bag inflator. The air bag has an interior cavity and an airbag opening leading into the interior cavity. In the event of air bagdeployment, the air bag inflator discharges an inflation gas out of anoutlet generally to the side of the vehicle occupant. A vane thenredirects the flow of inflation gas so that the air bag may deploytoward the vehicle occupant. In contrast to existing air bag modules,however, the vane of the inventive air bag module extends from the airbag opening into the interior cavity of the air bag. In this way, thevane is located within the insulating confines of the air bag. Thisunique location for the vane reduces heat loss significantly.Accordingly, the vane allows the inflation gas to maintain its hightemperature within the air bag while still redirecting the air bagtowards the vehicle occupant.

[0006] The vane is located near the air bag opening. Moreover, tofurther reduce temperature loss, the vane is sized smaller than the airbag opening. The vane may have a dimension, such as a width, less than adimension of the air bag opening, such as an opening width. By reducingthe size of the vane relative to the air bag opening, the hightemperature of the inflation gas is further maintained.

[0007] A support may be used to hold the vanes in place relative to theair bag. The support may comprise a number of vanes each spaced next toan air bag opening. To reduce heat loss, the air bag may be attachedaround the support. The support may be rectangular in shape. Inaddition, pressure relief holes may be provided in the support to adjustthe distribution of inflation gas across the air bag opening.

[0008] The invention further encompasses an inventive manufacturingtechnique. A vane is placed next to an air bag opening on a support.Rather than placing the vane outside of the air bag, the vane isextended into the air bag. The air bag is then attached around thesupport. This technique thus permits inflation gas to be directed towardthe vehicle occupant without a significant loss of heat.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The various features and advantages of this invention will becomeapparent to those skilled in the art from the following detaileddescription of the currently preferred embodiment. The drawings thataccompany the detailed description can be briefly described as follows:

[0010]FIG. 1 illustrates a cross-sectional view of the inventive air bagmodule, including air bag, air bag inflator, and vanes extending fromthe air bag opening into the interior cavity.

[0011]FIG. 2 illustrates a perspective view of the vanes of FIG. 1.

[0012]FIG. 3 illustrates a bottom view of the inventive air bag moduleof FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013]FIG. 1 illustrates inventive air bag module 10 comprising air bag14 and air bag inflator 30. Like existing air bag modules, air bag 14has an exterior surface 22 that defines an interior cavity 18. Moreover,air bag inflator 30 has outlets 34, which, during deployment, directinflation gas along the direction of path A. Path A may be at a 30°angle to an axis of inflator 30, axis X. Without guide structures, airbag 18 would tend to deploy generally along the direction of path A.

[0014] To address this issue, air bag module 10 has support 46 toredirect the flow of inflation gas from air bag inflator 30. Air bagsupport 46 has air bag openings 26 that permit the passage of inflationgas into interior cavity 18 from outlets 34 of air bag inflator 30. Inaddition, support 46 has vanes 38 that extend at an angle relative tosupport 46 as shown. The disclosed angle is approximately 60° or a 120°angle relative to axis X. As further shown in FIG. 1, each vane 38 islocated adjacent each air bag opening 26. As a consequence of thelocation of vanes 38 relative to air bag openings 26, inflation gaspasses through air bag openings 26 along vanes 38 in the direction ofpath B, a path transverse to path A. The net effect is to cause air bag14 to expand in the direction of path C towards a vehicle occupant.Because vanes 38 extend from air bag openings 26 into interior cavity18, heat loss is significantly minimized. Air bag 14 and hot inflationgas within air bag 14 insulates vanes 38 and allows the inflation gas tomaintain its high temperature to optimally expand air bag 14.

[0015] In further contrast to existing air bag modules, the inventiveair bag module 10 has vanes 38 sized smaller than air bag openings 26.As shown in FIG. 2, support 46 comprises planar member 48 having air bagopenings 26 located adjacent to vanes 38. Vanes 38 have width V_(w)while air bag openings have air bag opening width O_(w). Here, V_(w) ispreferably less than O_(w). Also, the length of vanes V_(L) ispreferably less than the length of openings O_(L), In this way, heatloss through vanes 38 is further minimized by keeping vanes 38 smallerthan air bag openings 26.

[0016] In addition, support 46 has pressure relief holes 50. As shown inFIG. 1, pressure relief holes 50 are located between outlets 34 and airbag interior 18. Although not effective in redirecting inflation gasflow, pressure relief holes serve to improve the distribution ofinflation gas around outlets 34. The size and location of pressurerelief valves will vary with the pressure from air bag inflator 30 andthe location of outlets 34.

[0017] In addition, support 46 has bolt holes 62 that receive bolts 58.As shown in FIG. 1 and FIG. 3, air bag 14 is attached to support 46 by abolt 58 and nut 66 connection. It should be noted that air bag 14surrounds support 46 to prevent the leakage of inflation gas aroundsupport 46 as well as to maintain the high temperature of inflation gaswithin interior cavity 18 of air bag 14.

[0018] Thus, air bag module 10 is made by placing vanes 38 adjacent toair bag openings 26. Vanes 38 are extended into interior cavity 18 ofair bag 14. Air bag 14 is then attached around support 46. Support 46preferably comprises a metal to withstand the high temperature of theinflation gas. Support 46 may be produced by stamping, such as by aprogressive die. Notch 54 may be provided to assist the movement ofsupport 46 within the progressive die.

[0019] The aforementioned description is exemplary rather that limiting.Many modifications and variations of the present invention are possiblein light of the above teachings. The preferred embodiments of thisinvention have been disclosed. However, one of ordinary skill in the artwould recognize that certain modifications would come within the scopeof this invention. Hence, within the scope of the appended claims, theinvention may be practiced otherwise than as specifically described. Forthis reason the following claims should be studied to determine the truescope and content of this invention.

What is claimed is:
 1. An air bag module, comprising: an air bag havingan interior cavity; at least one air bag opening in communication withsaid interior cavity; an air bag inflator having an outlet for inflatingsaid air bag; and at least one vane extending from about said air bagopening into said interior cavity.
 2. The air bag module of claim 1wherein said outlet is disposed to direct an inflation gas along a firstdirection and said at least one vane is disposed to direct the inflationgas along a second direction transverse to said first direction.
 3. Theair bag module of claim 1 wherein said at least one vane is adjacent tosaid at least one air bag opening.
 4. The air bag module of claim 1wherein said at least one vane has a vane dimension smaller than anopening dimension of said at least one air bag opening.
 5. The air bagmodule of claim 4 wherein said vane dimension comprises a vane width andsaid opening dimension comprises an opening width, said vane widthsmaller than said opening width.
 6. The air bag module of claim 1wherein said at least one vane comprise a plurality of vanes and said atleast one air bag opening comprises a plurality of air bag openings,each of said plurality of vanes adjacent to each of said plurality ofair bag openings.
 7. The air bag module of claim 6 including a supportholding said plurality of vanes and defining said plurality of air bagopenings.
 8. The air bag module of claim 7 wherein said support isattached to said air bag.
 9. The air bag module of claim 7 wherein saidsupport comprises a planar member.
 10. The air bag module of claim 7including at least pressure relief hole on said support spaced betweensaid outlet and said interior cavity, said at least pressure relief holein communication with said interior cavity.
 11. An air bag module,comprising: an air bag having an interior cavity; at least one air bagopening in communication with said interior cavity an air bag inflatorhaving an outlet for inflating said air bag, said outlet disposed todirect an inflation gas along a first direction; and at least one vaneextending into said interior cavity and adjacent to said at least oneair bag opening, said at least one vane disposed to direct the inflationgas along a second direction transverse to said first direction.
 12. Theair bag module of claim 11 wherein said at least one vane has a vanedimension and said at least one air bag has an opening dimension, saidvane dimension smaller than said opening dimension.
 13. The air bagmodule of claim 12 wherein said vane dimension comprises a vane widthand said opening dimension comprises an opening width, said vane widthsmaller than said opening width.
 14. The air bag module of claim 11wherein said at least one vane comprises a plurality of vanes and saidat least one air bag opening comprises a plurality of air bag openings,each of said plurality of vanes adjacent to each of said plurality ofair bag openings.
 15. The air bag module of claim 14 including a supportholding said plurality of vanes and defining said plurality of air bagopenings.
 16. The air bag module of claim 15 wherein said support isattached to said air bag.
 17. The air bag module of claim 15 whereinsaid support comprises a planar member.
 18. The air bag module of claim15 including at least pressure relief hole on said support spacedbetween said outlet and said interior cavity, said at least pressurerelief hole in communication with said support.
 19. A method ofmanufacturing an air bag, comprising the steps of: placing a vaneadjacent to an air bag opening on a support; extending the vane into aninterior cavity of an air bag; and attaching the air bag around thesupport.
 20. The method of manufacturing the air bag of claim 19 whereinthe air bag opening has an opening dimension and the vane has a vanedimension wherein the vane dimension is smaller than the openingdimension.